Effect of cold temps on charging?

I live in Colorado where we're having record low temps.

Plugged in my Level 1 charger yesterday afternoon after returning with 16 miles projected left in battery.

This morning MFM shows charging completed (100%) at 6:06 a.m., but also shows 45 miles as the new range.

Is this normal??? And realistic?

Yes: Remember the range shown is an estimate by the "guess-O-meter". Its not using a constant factor converting the battery % to miles to drive.

Given that its cold temps you've probably been driving around with the heater on which consumes more electricity than the drive motor in some cases.
Read up here:
http://jamiegeek.myevblog.com/2013/10/12/the-guess-o-meter/

Thanks, jm....

You're right; yesterday I had been out and about using both the heater and the heated seats (Geeeez, it was cold!)

After getting over the shock/confusion about a fully charged FFE with a GOM of 45 mi., I understand the effect better. It seems the validity and accuracy of the GOM are likely enhanced by its being able to sample over longer periods of time.

I am supposing if I dare go out today (although i'ts now a balmy 14 degrees), if I did NOT use any severe drain (e.g. the heaters), that "45" GOM will rise significantly? I suppose I should take the car out to see how high the GOM might go. I suspect will be less than previous, fully-charged, and I suppose, too, that however lower that new guess might be, is the cost of low-temp operation.

I did read the sub-link you provided...and I wonder about this quote:
An extreme case of this: My coworker took his FFE down the Woodward Dream Cruise this past summer where he had to drive it under 10 mph for quite a few miles. His GOM rose and rose and rose topping 200 miles at one point!

If the coworker traveled at that same 10mph under fairly constant conditions for a long time, mighn't he expect to realize something close to the GOM of 200?

jkbrand said:

This morning MFM shows charging completed (100%) at 6:06 a.m., but also shows 45 miles as the new range.

Is this normal??? And realistic?

Click to expand...

Yes, it might perfectly normal. As jmueller065 described, the estimate is "simply math" and is based on how you have been driving the car and consuming energy. It does not necessarily indicate that anything "has changed" with the battery, or that less energy has been stored.

In basic terms, the car's current estimate really all depends on your current average Wh/mi. Do you know what is it? With a 45 mile estimate on a full charge, I would guess that it is something well above 400:

19 kWh (usable battery capacity of the FFE) / 45 = ~420 Wh/mi

Although the car's estimation algorithm is somewhat more complex than this simple equation, you can throw your average Wh/mi into this equation is see if the car's estimate makes sense. (Note that I use 19 kWh for the battery capacity since most people have measured anywhere from 18.5 kWh to 19.5 kWh capacity with their FFE, so I split the difference for illustration.)

Anyway, to get your full charge estimate back up, simply use less energy per mile. Accelerate slowly. Brake carefully. Drive slower. Avoid using the climate controls (esp. heat) if possible.

One way to monitor your average Wh/mi is to reset one of the trip meters in the left-hand dash display right after your next full charge. Then, as you drive, not only will the meter count miles driven so far on the charge, but it will also keep track of the average Wh/mi. (Note that resetting the trip meter only affects the trip meter, it does not affect the car's internal average Wh/mi used for the mileage estimate. The trip meter is merely informational.)

In my experience the FFE seems to weight more recent trips driving Wh/m average over longer term average for the GOM range estimate. That appears to be why it moves around a lot even while driving if you drive slow/downhill for a few miles or drive faster/uphill for a few miles. So I've been getting higher range estimates right now compared to what would be expected from the lifetime Wh/m average display, since I've been getting lower Wh/m on recent trips.

Note also that MFM's full battery range prediction, just like the car's dash-displayed range, will vary depending on whether you left the cabin heater on or off. If you start your car and see 45 miles range and the heat is on, simply turning off the heater will cause the range to instantaneously jump. MFM's predictions should match the car dash's prediction, though sometimes they're off by a mile or two, or sometimes MFM shows a heated drive range prediction even though you left the car unheated. That's MFM for you.

As far as the magnitude of range loss caused by using the heater:in general the slower your average speed, the longer your drive takes so the longer you run the heater, drawing a fairly constant power whether you are moving or standing still in traffic. At those slow speeds, driving itself will use less energy. So the biggest heater-induced range hit is at slow speeds. Last winter my rush hour commutes where I average 10mph saw predicted ranges around 80 without heat, vs 40 with heat. On winter weekends when I could drive faster, my range predictions would be more like 70 vs 50. I have found little difference in predicted range between 'normal cold' like 30s vs bitter cold like negatives. But it's a lot harder to forgo cabin heating in that bitter cold!

jkbrand said:

If the coworker traveled at that same 10mph under fairly constant conditions for a long time, mighn't he expect to realize something close to the GOM of 200?

Click to expand...

Yes: If you can drive several miles at a constant 10 mph you probably would be able to go 200 miles in your FFE (and the GOM would be correct/accurate). This would be a bit difficult to do since the cruise control doesn't operate below about 20 mph, and of course there is traffic.

This doesn't relate to the OP, but the topic title is quite appropriate for my question. I've noticed on these recent cold days that as soon as my wife comes home and plugs in the car it starts charging immediately even though the next Go Time isn't until the following morning. It doesn't fully charge but charges for awhile.

Is this because the battery is very cold? Has anyone else experienced this?

hybridbear said:

It doesn't fully charge but charges for awhile.

Click to expand...

How long is "a while"?

hybridbear said:

Is this because the battery is very cold? Has anyone else experienced this?

Click to expand...

A possible explanation.... I remember reading somewhere that the car charges for a little while when you first plug it in (even with Go Time) so it can accurately estimate how long the charge will take. Otherwise, how is the car supposed to know the circumstances under which it will be charging later, and thus determine when to begin charging in order to meet the Go Time? (Although we do indicate 120 versus 240 volts in the charging profile, that isn't enough information for the car to accurately predict the required charging time... it also needs to know how much current it will have access to.)

That said, I also remember that this "test charge" only lasted for about 15 minutes or something (which is what you meant by "a while"). You might be seeing perfectly normal behavior, and nothing to do with the cold.

I have noticed this when I used to park it outside and it was very cold:
http://jamiegeek.myevblog.com/2013/11/24/does-the-car-charge-to-keep-warm/

Some numbers on that:
http://jamiegeek.myevblog.com/2013/11/27/some-numbers-on-the-cold/

WattsUp said:

hybridbear said:

It doesn't fully charge but charges for awhile.

Click to expand...

How long is "a while"?

hybridbear said:

Is this because the battery is very cold? Has anyone else experienced this?

Click to expand...

A possible explanation.... I remember reading somewhere that the car charges for a little while when you first plug it in (even with Go Time) so it can accurately estimate how long the charge will take. Otherwise, how is the car supposed to know the circumstances under which it will be charging later, and thus determine when to begin charging in order to meet the Go Time? (Although we do indicate 120 versus 240 volts in the charging profile, that isn't enough information for the car to accurately predict the required charging time... it also needs to know how much current it will have access to.)

That said, I also remember that this "test charge" only lasted for about 15 minutes or something (which is what you meant by "a while"). You might be seeing perfectly normal behavior, and nothing to do with the cold.

Click to expand...

24 minutes today, similar amount of time other days. This has only happened the last couple days when the ambient temp has been in the low 20s. After being parked all day the battery is likely barely warmer than ambient temps.

jmueller065 said:

I have noticed this when I used to park it outside and it was very cold:
http://jamiegeek.myevblog.com/2013/11/24/does-the-car-charge-to-keep-warm/

Some numbers on that:
http://jamiegeek.myevblog.com/2013/11/27/some-numbers-on-the-cold/

Click to expand...

Thanks! Sounds like what we're seeing. The car charges immediately as soon as we get home for a brief period. Then it stops and waits to finish charging overnight.

Now that I'm logged in on the computer I can see a better picture of this.

On Thursday the car began charging as soon as it was plugged in and charged for 24 minutes.

On Wednesday it began charging as soon as it was plugged in and charged for 12 minutes.

On Tuesday it did the same thing and charged for 16 minutes.

On Monday it did the same thing and charged for 15 minutes.

Monday was the first day that the car was parked outside all day at work in temps below 25 F. My guess is that the car was trying to heat the HVB.

The car did the same thing Saturday evening, charging for 24 minutes immediately upon being plugged in. Monday it charged for 23 minutes. Tuesday it charged for 26 minutes, the longest yet. Yesterday (Wednesday) it also started charging immediately. I set it to complete the charge because we wanted the Fusion plugged in to the EVSE overnight.

Last night I had to add windshield washer fluid and I heard a low humming/whirring noise. Was that the TMS working to heat the battery? I had heard it working in the summer to cool the battery and I could open the hood and see the fan spinning. I had not heard it making this low hum before though.

The initial charge when it is set to delayed charging is to heat the battery to 50F. You can tell that battery heating is active by listening for the initial charge contactor closing, and then the main traction contactor closing a few seconds later (5-10 seconds) associated also with a uptake in the battery coolant pump speed. The battery heaters are 3 300 watt (900 watts total of heating) inline heaters that operate off of the 12V system. When there is a large demand on the 12V system during charging, the DC-DC converter engages (which requires the traction circuit to be energized). Otherwise, the charger provides float charging and the DC-DC converter is off.

sefs said:

The initial charge when it is set to delayed charging is to heat the battery to 50F. You can tell that battery heating is active by listening for the initial charge contactor closing, and then the main traction contactor closing a few seconds later (5-10 seconds) associated also with a uptake in the battery coolant pump speed. The battery heaters are 3 300 watt (900 watts total of heating) inline heaters that operate off of the 12V system. When there is a large demand on the 12V system during charging, the DC-DC converter engages (which requires the traction circuit to be energized). Otherwise, the charger provides float charging and the DC-DC converter is off.

Click to expand...

sefs, I would like to find more specifics like this about the car. Where did you find this info? Thanks

sbeilman said:

sefs said:

The initial charge when it is set to delayed charging is to heat the battery to 50F. You can tell that battery heating is active by listening for the initial charge contactor closing, and then the main traction contactor closing a few seconds later (5-10 seconds) associated also with a uptake in the battery coolant pump speed. The battery heaters are 3 300 watt (900 watts total of heating) inline heaters that operate off of the 12V system. When there is a large demand on the 12V system during charging, the DC-DC converter engages (which requires the traction circuit to be energized). Otherwise, the charger provides float charging and the DC-DC converter is off.

Click to expand...

sefs, I would like to find more specifics like this about the car. Where did you find this info? Thanks

Click to expand...

The service manual is availability for $10.95 for 72 hours, more for more time reading. It's definitely worth a read to understand the systems on the vehicle on a more technical level.
http://www.helminc.com/helm/product2.asp?Make=FRD&Model=FOCU&Year=2012&Category=37&class_2=FRD&mk=Ford&yr=2012&md=Focus&dt=Online+Service+Information+%28OSI%29&module=&from=result&Style=helm&Sku=FCS2012FZWEBD&itemtype=N

Thanks. That looks like a great resource. I saw they also have a paper book of wiring diagrams for the FFE for $79.

I got my wiring manual on ebay for under $20.

We had one day where the high was around 0 and the low temp was about -15. The car sat outside all day at my wife's office in those temps. When she got home the car charged for 59 minutes, buzzing the entire time while heating the HVB.